Canadian Letters Patent 1,099,268 (corresponding to U.S. Pat. No. 4,128,658 and U.K. Patent 1565966) teaches the medicine Ranitidine and salts thereof (including the hydrochloride salt) and processes for the manufacture thereof.
Canadian Letters Patent 1,202,638 (corresponding to U.S. Pat. Nos. 4,521,431 and 4,672,133) purports to teach a specific new form of Ranitidine Hydrochloride which form the Inventor, Mr. Derek L. Crookes, termed "Form 2" to purportedly distinguish the purportedly new form from the purported forms taught in the original patents (Canadian Letters Patent 1,099,268, U.S. Pat. No. 4,128,658, U.K. Patent 1565966 and all corresponding patents and which form taught by these patents the Inventor identified as Form 1 forms of Ranitidine Hydrochloride).
Mr. Crookes asserted in the later patents (Canadian Letters Patent 1,202,638 and U.S. Pat. Nos. 4,521,431 and 4,672,133) that the procedures for producing (crystallizing) Ranitidine Hydrochloride in accordance with the teachings of said U.K. Patent 1565966 (and thus under corresponding U.S. Pat. No. 4,128,658 and Canadian Letters Patent 1,099,268)
does not have the desirable features of a manufacturing process described above and Form 1 of the hydrochloride salt has unsuitable filtration and drying characteristics PA1 Bulk Density not less than about 0.23 gm/ml PA1 Tap Density not less than about 0.28 gm/ml PA1 Melting Point same as Form 1 PA1 Infrared Spectrum same as Form 1 PA1 Raman Spectrum same as Form 1
(page 2, line 35-page 3, line 1 of Canadian Letters Patent 1,202,638)
The only method by which Mr. Derek L. Crookes could overcome the deficiencies and limitations of the purported Form 1 Ranitidine Hydrochloride was to develop a purported new form of Ranitidine Hydrochloride (identified as Form 2 to distinguish the purported new form from the old form (termed Form 1)) and which purported Form 2 Ranitidine Hydrochloride overcame the deficiencies and limitations of the purported Form 1 Ranitidine Hydrochloride.
It is therefore an object of this invention to provide an improved form of Form 1 Ranitidine Hydrochloride which overcomes the previously described deficiencies and limitations of previous forms of Form 1 Ranitidine Hydrochloride and to provide Form 1 Ranitidine Hydrochloride which has better filtration and drying characteristics.
It is a further object of this invention to provide processes for the manufacture of the improved form of Form 1 Ranitidine Hydrochloride which processes provide the improved form of Form 1 Ranitidine Hydrochloride consistently and in goods yields.
Further and other objects of the invention will be realized by those persons skilled in the art from the following Summary of the Invention and Detailed Description of Embodiments thereof.
In this regard should other salts of Ranitidine in a form which has unsuitable filtration and drying characteristics be developed, it is a further object of this invention to provide processes which can be used to produce a better form of the salt of Ranitidine which has acceptable filtration and drying characteristics.